The present invention relates to photodetectors. In particular, the present invention relates to improved infrared sensitive Schottky barrier photodiodes.
In recent years, lead tin telluride and lead tin selenide have been developed as potential infrared detector materials for the important 8 - 14 micron wavelength region. The energy gap or bandgap of these materials may be varied by varying the ratio of lead, tin, selenium, and tellurium in the materials.
Schottky barriers have been used to fabricate infrared detectors on lead tin telluride and also on lead telluride, using a barrier forming material such as lead, indium, and others. Similar Schottky barriers may be formed on lead tin selenide.
One problem which has been encountered with Schottky barrier infrared detectors for the 8 - 14 micron radiation region has been the low zero bias resistance of the detectors. The resistance of the detector is lower than that necessary for optimum detector performance.